Feline Infectious Peritonitis (FIP) is a fatal disease of cats caused by a mutated coronavirus. The coronavirus mutates only in certain cats so research has suggested that the risk of the virus being transmitted from an infected cat to other cats is unlikely. Contact with faeces is a possible route of infection. Young cats and immunocompromised cats have an increased risk of infection.

There are two forms of FIP: wet FIP where fluid accumulates in the abdomen or chest; and dry FIP where fluid accumulation is less likely but weight loss, depression and fever are present. Dry FIP is difficult to diagnose because the signs are non-specific and similar to other diseases.